All enumeration type fields should be commented as Javadoc style.
<p>Examples:</p>
<pre>
    public enum TestEnum {
        /**
         * agree
         */
        agree("agree"),
        /**
         * reject
         */
        reject("reject");

        private String action;

        TestEnum(String action) {
            this.action = action;
        }

        public String getAction() {
            return action;
        }
    }
</pre>